How can I avoid seafood economic fraud?

To get the best value for your money when buying seafood, it's important to know what you're buying. Be wary of unusual bargains--some seafood is seasonal. If there is a considerable difference between the price of a fresh product and what you are accustomed to paying, it could be that it is from the last season's frozen inventory. Buy from a reputable dealer. And if the fish you choose looks or smells different from what you expect, discuss it with the fish market manager.

Look for firm, shiny flesh that bounces back when touched. If the head is on, the eyes should be clear and bulge, and the gills should be bright red. The fish should not smell "fishy"--it should smell like a fresh ocean breeze.

It's easy to miss the telltale signs of species substitution. Sometimes, taste or consistency is the only way to detect it. If you feel you have purchased something different from what was represented, tell your fish market manager.

Here's how to distinguish some common species:

• Haddock has a dark lateral line along the skin surface.

• Skinless cod fillets have a distinctive white papery membrane along the belly and a white line of fat along the lateral line of the fillet.

• Shark and swordfish look alike, but shark has a dark streak of flesh in the center and rough skin along the edge.

• Red snapper comes only from the southern Atlantic Ocean and the Gulf of Mexico (ask your retailer where the snapper originated).

• Orange roughy comes only from Australia or New Zealand and always arrives frozen. It may be sold thawed, but it must be labeled as previously frozen.

• Scrod is not a type of fish. The term originated in the Boston area to describe the catch of the day. It is a fish under two and a half pounds that is either cod, haddock or pollock. Such fish should be labeled in the market or listed in a restaurant as "scrod cod," "scrod haddock," or "scrod pollock."